拉筋对两层两跨钢-混凝土组合框架结构抗震性能的影响

PSEUDO-STATIC TESTS OF STIRRUP-CONFINED SQUARE CFST TWO-STORY TWO-SPAN COMPOSITE FRAME STRUCTURE

该文开展了2榀2层2跨缩尺比例为2/5的水平往复荷载下方钢管混凝土柱-钢混凝土组合梁平面框架滞回性能试验研究,分析了柱端拉筋强柱构造对钢-混凝土组合框架结构抗震性能的影响。运用有限元软件ABAQUS建立该平面框架有限元模型,在试验验证的基础上开展柱端拉筋等效配箍率对组合平面框架抗震性能影响规律的研究。分析结果表明:柱端拉筋降低了钢管与混凝土之间的滑移、约束混凝土并加强了钢管对混凝土的约束作用,进而提高了柱端抗弯承载力与耗能能力,间接改变了梁柱线刚度比和抗弯承载力比,挖掘了钢梁的耗能潜力;柱端拉筋强柱构造措施有效提高了钢-混凝土组合平面框架结构的刚度、承载力和耗能能力,分别达70%、20%和50%以上。

An experimental study on two two-story-two-span CFST frames with or without internal stirrups subjected to horizontal cyclic loading was conducted.The frame specimens were scaled down to 2∶5.The objective of this study is to investigate the influence of stirrups welded inside the CFST columns on the aseismic performance of the frames.Numerical analysis was carried out using ABAQUS,and the finite element model was verified by comparing the test results.Based on the FE models,the influence of the equivalent stirrup ratio was investigated.The experimental and numerical analysis results indicate that the stirrups reduce the slippage between steel tube and infilled concrete and,strengthen the confinement effect of steel tube on infilled concrete at same time.Moreover,the flexural bearing capacity and energy dissipation capacity of the frames were improved.The stirrups also change the ratio of line stiffness and flexural bearing capacity between beam and column indirectly.Compared with the conventional frames,the frames designed using‘strong columns’can improve the stiffness,bearing capacity and energy dissipation capacity of the frames by more than 70%,20%and 50%,respectively.